Prospecção de biomarcadores moleculares de resistência de tomateiro à murcha bacteriana causada pela Ralstonia pseudosolanacearum

Abstract

Tomato (Solanum lycopersicum L.) is one of the most economically important vegetables in the world. Ralstonia pseudosolanacearum (Rp) is a phytopathogenic bacterium that infects the xylem of plants, causing the devastating disease known as bacterial wilt (MB), which attacks more than 200 plant species worldwide. The objective of this work was to clarify the mechanisms of resistance and susceptibility, at the proteomic level, of two cultivars resistant to Rp: Hawaii 7996 and Yoshimatsu and a susceptible Caline IPA-7, in response to inoculation of the strain CCRMRs202 of Rp, at four days after inoculation. The methodology consisted of the extraction of total soluble proteins, injection into a nano-LC-MS/MS mass spectrometer, analysis of the spectra obtained and identification of proteins in MaxQuant software, statistical analysis and selection of proteins differentially accumulated between treatments in Perseus and categorization by gene ontology in UniProt and Blast2GO v. 6.0. A total of 1385 proteins were obtained when comparing the cultivars Yoshimatsu and Caline IPA-7 and 1306 proteins when comparing the cultivars Hawaii 7996 and Yoshimatsu. Of these, those directly linked to the defense response were selected by gene ontology. Several proteins related to pathogenesis (PR-proteins) that have antimicrobial action were identified, including PR1, PR5, PR10 and PR14; the universal stress protein (PHOs/USP), known to promote resistance to multiple stresses, regulation of ROS homeostasis and regulation of plant growth/development; the annexins, related to the anti-oxidant system and pectinoesterase e xyloglucan endotransglucosylase (XET), both related to the cell wall. Their accumulation, either exclusively or differently in cultivars under stress, broadens the understanding of different strategies of resistance to the pathogen, and can significantly contribute to tomato genetic improvement programs in a process of assisted selection of genotypes resistant to bacterial wilt.